Thrombus detection device and method

ABSTRACT

A thrombus detection device comprising an elongate tube having at least one opening at a distal end of the elongate tube. A coupling is attached or formed at the proximal end of the elongate tube. The detection of the presence of a thrombus is performed by using a syringe to withdraw blood through the at least one thrombus detection opening at the distal end of the elongate tube. If little or no blood is withdrawn, or if the withdrawal of blood is more difficult than expected, the presence of a thrombus obstructing the openings is indicated.

Cross-Reference to Related Applications:

This application claims the benefit of priority to co-pending U.S.Provisional Patent Application Ser. No. 62/151,812 filed Apr. 23, 2015,which is herein incorporated by reference in its entirety. ThisApplication is related to commonly owned and co-pending U.S. patentapplication Ser. No. 14/137,931 filed Dec. 20, 2013, which is acontinuation of U.S. patent application Ser. No. 12/684,839, filed Jan.8, 2010, now U.S. Pat. No. 8,613,753, which, in turn, is acontinuation-in-part of U.S. patent application Ser. No. 11/849,225,filed Aug. 31, 2007, now U.S. Pat. No. 8,668,712; the contents of eachof the foregoing are incorporated by reference herein.

FIELD OF THE INVENTION

The present invention pertains generally to the field of devices for usein the treatment of venous thrombosis. More particularly, the presentinvention relates to an apparatus for detecting a thrombus captured in avena cava filter within a patient's blood vessel.

BACKGROUND

A deep vein thrombosis (DVT) is a blood clot, or thrombus, that forms ina vein. A principal risk of a DVT is that it will embolize and become alife-threatening pulmonary embolism (PE). The disease process venousthromboembolism (abbreviated as VTE or DVT/PE) can refer to DVT and/orPE. The accepted standard of care for patients with DVT is anticoagulanttherapy. Inferior vena cava (IVC) filters are typically reserved forthose patients who fail anticoagulant therapy, or have a complication orcontraindication to anticoagulant therapy. In some cases, bothanticoagulant therapy and an IVC filter may be used to treat patientswith DVT.

An IVC filter is deployed in the vena cava to capture thrombotic orembolic material before it can cause a PE. The filter may be deployedpermanently, or as a temporary IVC filter that may be retrieved after aperiod of time. A temporary IVC filter may be deployed whilethrombolytic medication is administered to reduce the thrombus. Thetemporary IVC filter would capture any parts of the thrombus that mightcome loose while the thrombolytic medication is administered. After aperiod of time, the risk of a PE may be lessened and the filter may beretrieved.

The use of an IVC filter, particularly a temporary IVC filter, mayrequire periodic monitoring to detect whether and to what extentthrombotic material is captured by the IVC filter. As the IVC filtercaptures thrombotic material, the filter may become burdened with somuch thrombotic material that it forms an obstacle for blood flow to theheart. An overly burdened temporary IVC filter may also be filled withenough thrombotic material to affect the collapsibility of the filtermaking the filter more difficult to retrieve, increasing the risk ofdislodging the thrombotic material and causing a PE. Prior to retrieval,thrombus captured in an overly-burdened filter may be treated to reducethe size of the thrombotic material. Treatment may be by chemical means,such as by administration of a thrombolytic agent, by mechanical means,such as by employing a structure that mechanically disrupts thethrombotic material, by pressure such as pressurized fluid injection orsonication of the thrombus or by thermal means, such as by laser orother energetic means for disrupting the thrombus. It will be understoodthat the foregoing means for treating the thrombus captured in the IVCfilter are exemplary only and non-limiting. Alternative means fortreating or reducing the thrombus captured within the IVC filter as maybe currently or hereinafter known in the art are also contemplated bythe present invention. Under all circumstances, however, prior toremoving a temporary IVC filter, it is highly desirable to detect boththe presence of thrombus in the filter and evaluate its size and effecton withdrawing the temporary IVC filter while controlling the risk ofpulmonary embolism as a result of thrombotic material being releasedfrom the temporary IVC filter during retrieval.

Known methods of detecting the presence of a thrombus in an IVC filterrely on the use of expensive imaging processes and medical imagingequipment. When it is desired to determine if a thrombus is present inan IVC filter deployed in a patient, the patient is typically moved toan imaging facility. The area in which the filter is deployed in thepatient's body is imaged. If the imaging is performed using x-rays, theimaging generates cavograms or angiograms, which are then analyzed todetermine if a thrombus is present in the filter. Other such imagingmethods include intravascular ultrasound (“IVUS”), venography, and CTscans.

It would be desirable to be able to determine at the patient's bedsidewhether a thrombus is present in the IVC filter without the need forimaging, or to make preliminary determinations of the presence of athrombus in the IVC filter prior to imaging to quantify the presence andsize of the thrombus.

SUMMARY OF THE INVENTION

In one embodiment, a thrombus detection device comprises an elongatetube comprising a tube lumen extending at a substantially constant innerdiameter from a first opening at a proximal end to a distal tubeportion. The distal tube portion comprises a distal portion lumenextending at an increasing inner diameter to a second opening wider thanthe first opening. The second opening is sufficiently wide to permitentry of a thrombus into the distal portion lumen. The device fordetecting the thrombus includes a coupling at the proximal end of theelongate tube which is used to couple a pump or other means, such as asyringe, for withdrawing blood or fluid from the elongate tube.

For purposes of illustration only, the present application will refer toa syringe as the pump or other means. It is expressly intended, however,that the embodiments disclosed herein are not intended to be limited asyringe as a particular type of pump or other means to draw blood intothe elongate tube. Rather, other types of pumps, such as a squeeze bulb,a piston pump, a rotary pump, a syringe pump, a vacuum pump, forexample, are expressly included within the scope of the embodimentsdisclosed herein. When coupled to the elongate tube, the pump or syringeis used to draw blood into the distal portion lumen and through the tubelumen of the elongate tube. The presence of a thrombus is indicated bythe volume of blood drawn by the pump, i.e., when less blood can bedrawn than expected due to obstruction of the tube lumen by the thrombusin the distal portion lumen.

In another embodiment, the elongate tube may be deployed by insertingthe tube into a sheath that guides the elongate tube to the site ofinterest.

In another embodiment, the elongate tube may be deployed by insertingthe tube into a lumen of a single or multi-lumen catheter. The cathetermay be of the type that includes an attached IVC filter and a port forthe lumen that opens proximal to the IVC filter.

The elongate tube in embodiments disclosed herein may be a tube memberwith a flexible end member attached at the distal end of the tubemember. The flexible end member may have a first opening configured toattach to the distal end of the single tubular member and a secondopening wider than the first opening. In another embodiment, theelongate tube may be a single component made of a flexible material andhaving a first opening at the proximal end and a second opening widerthan the first opening at the distal end.

In another embodiment, a device is provided for detecting a thrombus,the device comprising an elongate tube with at least one tube lumenextending at a substantially constant inner diameter from a firstopening at a proximal end to a distal tube portion. The distal tubeportion includes a plurality of openings in fluid communication with atleast one of the tube lumens. A coupling is formed or attached at theproximal end of the elongate tube. The coupling is configured toremovably couple a syringe or pump, as previously described above, tothe first opening of the elongate tube. The syringe is used to drawblood into the at least one thrombus detection opening and through thetube lumen of the elongate tube. The detection of a thrombus is made byusing the syringe to draw blood through the elongate tube. The presenceof a thrombus is indicated when less blood can be drawn than expecteddue to obstruction of at least some of the plurality of openings.

Various advantages, aspects and novel features of the present invention,as well as details of an illustrated embodiment thereof, will be morefully understood from the following description and drawings. Othersystems, methods and features of the invention will be or will becomeapparent to one with skill in the art upon examination of the followingfigures and detailed description. It is intended that all suchadditional systems, methods, features and advantages be included withinthis description, be within the scope of the invention, and be protectedby the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example of a thrombus detectiondevice used with a catheter having an IVC filter.

FIG. 2A is a perspective view of an example of an elongate tube fordetecting a thrombus.

FIG. 2B is a detail view of the example of an elongate tube fordetecting a thrombus shown in FIG. 2A at Detail A.

FIG. 2C is a side view of the example of an elongate tube for detectinga thrombus shown in FIG. 2A.

FIG. 2D is a detail view of the example of an elongate tube fordetecting a thrombus shown in FIG. 2A at Detail D.

FIG. 3A is a perspective view of another example of a thrombus detectiondevice.

FIG. 3B is another view of the example of a thrombus detection device ofFIG. 3A.

FIG. 4A is a perspective view of another example of a thrombus detectiondevice.

FIG. 4B is a detail view of the example of a thrombus detection deviceof FIG. 4A at Detail C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the invention will now be described with reference to theFigures, wherein like numerals reflect like elements throughout. Theterminology used in the description presented herein is not intended tobe interpreted in any limited or restrictive way, simply because it isbeing utilized in conjunction with detailed description of certainspecific embodiments of the invention. Furthermore, embodiments of theinvention may include several novel features, no single one of which issolely responsible for its desirable attributes or which is essential topracticing the invention described herein. The words proximal and distalare applied herein to denote specific ends of components of theinstrument described herein. A proximal end refers to the end of aninstrument nearer to an operator of the instrument when the instrumentis being used. A distal end refers to the end of a component furtherfrom the operator and extending towards the surgical area of a patientand/or the implant.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the invention are to be construed to cover boththe singular and the plural, unless otherwise indicated herein orclearly contradicted by context. It will be further understood that theterms “comprises,” “comprising,” “includes,” and/or “including,” whenused herein, specify the presence of stated features, integers, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, integers, steps,operations, elements, components, and/or groups thereof.

Recitation of ranges of values herein are merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range, unless otherwise indicated herein, and eachseparate value is incorporated into the specification as if it wereindividually recited herein. The word “about,” when accompanying anumerical value, is to be construed as indicating a deviation of up toand inclusive of 10% from the stated numerical value. The use of any andall examples, or exemplary language (“e.g.” or “such as”) providedherein, is intended merely to better illuminate the invention and doesnot pose a limitation on the scope of the invention unless otherwiseclaimed. No language in the specification should be construed asindicating any nonclaimed element as essential to the practice of theinvention.

References to “one embodiment,” “an embodiment,” “example embodiment,”“various embodiments,” etc., may indicate that the embodiment(s) of theinvention so described may include a particular feature, structure, orcharacteristic, but not every embodiment necessarily includes theparticular feature, structure, or characteristic. Further, repeated useof the phrase “in one embodiment,” or “in an exemplary embodiment,” donot necessarily refer to the same embodiment, although they may.

As used herein, the term “syringe” shall refer to any device that may beused for withdrawing blood into a tube. For example, a syringe being asimple pump, any suitably configured pump may be used to aspirate bloodinto a tube. Such types of withdrawing devices include a wide variety ofpumps, such as a squeeze bulb, a piston pump, a rotary pump, a syringepump, a peristaltic pump or a vacuum pump.

Described below with reference to FIGS. 1-4B are examples of devices fordetecting a thrombus in a patient's blood vessel. The examples of thedevices for detecting a thrombus described below find particularlyadvantageous use in patients using an inferior vena cava filter (“IVCfilter”). After the IVC filter has been deployed, the filter may becomeburdened with thrombi. In some instances, it may be advantageous or evennecessary to break up the thrombotic material captured by the filter. Itmay be advantageous to determine if the filter has become burdened withthrombotic material at any time during the deployment of the filter.Typically, whether or not the filter has become burdened with thromboticmaterial is of most interest when the filter is to be removed. Usingexample implementations of devices for detecting a thrombus, thethrombotic material may be detected to determine the best way to managethe thrombotic material. The devices for detecting at thrombusadvantageously permit thrombus detection at a patient's bedside withoutthe need for expensive imaging equipment.

With reference to FIG. 1, according to one embodiment, a central venousaccess filter (“CVAF”) 100 is composed generally of a single lumencentral venous access catheter body 104 having a distal port 108associated with a catheter lumen 116, an IVC filter 106 attached to adistal end 105 of the catheter body 104. The catheter body 100 includesa hub 118 at the proximal end 103 to provide fluid coupling with thecatheter lumen 116.

The IVC filter 106 may be any suitable filtering device configured tocapture embolic material of a size that is sufficient to create a riskof a pulmonary embolism if it is not filtered. In an exampleimplementation, the IVC filter 106 may be a self-expanding structuremade of a plurality of struts formed to capture a thrombus. A firstplurality of struts may attach to the catheter body 102 and a secondplurality of struts interconnect to provide a filtering structure.

A thrombus detection device 101 is disposed within the catheter lumen116 of the catheter body 104 extending from the proximal end 103 to thedistal end 105 of the catheter body 104. The thrombus detection device101 is formed as an elongate tube 102 having a tube lumen 107 extendingat a substantially constant inner diameter from a first opening (notshown) at a proximal end 103 to a distal tube portion 111. The distaltube portion 111 includes a resilient section 113 formed of a resilientmaterial. The resilient section 113 of the distal tube portion 111 mayhave an increasing inner diameter as it extends distally from the distalportion lumen 109 to a second opening 110 that is greater than adiameter of the catheter lumen 116 at the distal end 105 of the catheterbody 102. In this configuration, the resilient section 113 has agenerally conical shape that opens distally relative to the longitudinalaxis of the thrombus detection device 101. The second opening 110 isconfigured to be sufficiently wide to permit thrombus 120 captured bythe IVC filter 106 to abut the resilient portion 111 and at leastpartially obstruct the second opening 110. It will be understood bythose skilled in the art that alternative configurations of theresilient section 113 are contemplated by the embodiments disclosedherein, with the proviso that the resilient section 113 should becapable of being brought into contact with the thrombus 120 withoutsubstantial risk of lysing or otherwise disrupting the thrombus 120 andthat it have a geometric configuration sufficient to engage the thrombus120 in a manner that obstructs the second opening 110 and makeswithdrawing blood through the elongate tube 102 more difficult than whenthe second opening 110 is not so obstructed.

The thrombus detection device 101 includes a coupling 112 at theproximal end 103 of the elongate tube 102. The coupling 112 isconfigured to removably couple a syringe 114 to the first opening of theelongate tube 102 where the syringe is used to draw blood into thedistal portion lumen 109 and through the elongate tube 102. When thesyringe 114 is coupled to the elongate tube 102, an attempt to withdrawblood may be initiated as the elongate tube 102 is advanced into theregion encompassed by the IVC filter 106 and in proximity to thethrombus 120, if present in the IVC filter 106. Gradation markings (notshown) that may be provided on the elongate tube 102 serve to indicatethe position of the distal portion lumen 109 relative to the filter 106.That is, that elongate tube 102 has a known length, the length of thecatheter body 104 and IVC filter 106 is known, and therefore theposition of the distal tube portion 111 relative to the IVC filter 106may be known by virtue of the graduation markings. As the elongate tube102 is advanced within the filter 106, blood is withdrawn by the syringe114. When the distal portion lumen 109 is in proximity to, adjacent toor abutting thrombus 120, the syringe 114 draws the thrombus 120 intothe distal portion lumen 109 of the elongate tube 102 and obstruct bloodfrom entering the tube lumen 107 creating a difficulty or inability towithdraw blood into the elongate tube 102 using the syringe 114. Thisdifficulty or inability to withdraw blood into the elongate tube 102 maythen be deemed as an indication that the thrombus 120 is present in thefilter 106.

The resilient section 113 of the elongate tube 102 may be of aresilient, flexible or elastic material capable of collapsing to areduced profile when inserted into the catheter body 104. Once the widersecond opening 110 extends out through the distal port 108 of thecatheter body 104, the resilient section 113 diametrically expands to anenlarged profile.

The elongate tube 102, including the resilient section 113, may be madeof a polymeric, metallic or combination polymeric/metallic biocompatiblematerial. The elongate tube 102 in FIG. 1 may be constructed as a singletube having the enlarged resilient section 113 be integral with theremainder of the elongate tube 102. Alternatively, elongate tube 102 maybe constructed of single tubular member and a substantially secondaryresilient member connected to the distal end of the tubular member asdescribed below with reference to FIGS. 2A-2D.

FIGS. 2A-2D illustrate different views of an example implementation ofan elongate tube 150 of a type that may be used in the example shown inFIG. 1. FIG. 2A is a perspective view of the elongate tube 150. FIG. 2Bis a detail view of the elongate tube shown in FIG. 2A at Detail A. FIG.2C is a side view of the elongate tube shown in FIG. 2A. FIG. 2D is adetail view of the elongate tube shown in FIG. 2C at Detail B.

Referring to FIGS. 2A-2D, the elongate tube 150 includes a tube member152, which forms the tube lumen 107 described above with reference toFIG. 1, and a flexible end member 154, which is the distal tube portion111 that forms the distal portion lumen 109 described above withreference to FIG. 1. The flexible end member 154 is attached to the tubemember 152 at a distal end of the tube member 152. The flexible endmember 154 attaches to the elongate tube 150 at a first end memberopening 155 sized to fit the opening of the elongate tube 150. Theflexible end member 154 opens distally to a second end member opening157 wider than the first end member opening 155.

The tube member 152 extends from a coupling 156 at a proximal end to theattachment to the flexible end member 154 at a distal end of the tubemember 154. A tube lumen 159 extends from the opening at the proximalend to the opening at the distal end. The tube member 152 and theflexible end member 154 may be made of the same or different materials.The tube member 152 may be made of any suitable biocompatible metallicor polymeric material with sufficient flexibility to allow insertioninto the tortuous routes that may be formed by body's blood vessels. Theflexible end member 154 may be made of any suitable biocompatiblemetallic or polymeric material with sufficient flexibility to collapsewhen inserted through a catheter and to self-expand to its un-collapsedstate when the flexible end member 154 extends out of the catheter. Thetube member 152 may be of any suitable length, which typically depend onthe length of the catheter used to deploy the elongate tube 150.

The coupling 156 may be a luer-lock in fluid communication with thefirst opening at the proximal end of the elongate tube 150, which is influid communication with the elongate tube lumen. However, any suitablemechanism for attaching a syringe, or any other suitable fluidwithdrawing device, so as to be in fluid communication with the lumen ofthe elongate tube may be used.

The flexible end member 154 shown in FIGS. 2A-2D is cone shaped.However, the flexible end member 154 may be any suitable shape such thatthe second end member opening 157 is wider than the first end memberopening 155. The shape of the flexible end member 154 should allow for athrombus to be funneled or guided in towards the first end memberopening 155 when blood is being withdrawn into the tube lumen 159. Thesize of the first end member opening 155 and the inner diameter of thelumen of the elongate tube 152 should be such that the smallestsignificantly sized thrombus would obstruct blood from flowing into thetube lumen 159 of the elongate tube 152. In another embodiment, theinner diameter of the tube lumen 159 may also be such that thrombi of adesired may pass through the tube lumen 159 along with blood beingwithdrawn.

The elongate tube 150 in FIGS. 2A-2D may be deployed as a thrombusdetection device by inserting the elongate tube 150 into a catheterdevice such as the catheter device 100 described above with reference toFIG. 1. In one embodiment, the elongate tube 150 includes a length L, asshown in FIG. 2C. The catheter device 100 shown in FIG. 1 is a singlelumen device. However, any single or multi-lumen catheter device may beused as well. For example, multi-lumen catheter devices such as thosedescribed in U.S. Pat. No. 8,613,753, which is incorporated herein inits entirety, incorporate multiple lumens, at least one of which may beconfigured for deployment of examples of the devices for detecting athrombus described herein. One advantage of using a multi-lumen catheterdevice is that a lumen may be configured for thrombus detection and atleast one other lumen may be used for infusion of thrombolytic agents,which may be dispensed when a thrombus is detected. The thrombusdetection lumen may be configured by providing an opening to thethrombus detection lumen at a location of the catheter that would putthe wide opening of the elongate tube near any thrombi captured in thefilter. A hub on the catheter device may be configured to provide anopening through which the elongate tube may be inserted into thethrombus detection lumen.

In an embodiment in which a single lumen catheter such as the catheter100 shown in FIG. 1 is used, the single lumen may be used for deploymentof the thrombus detection device as described above. When a thrombus isdetected, thrombolytic agents may be injected into the lumen of thethrombus detection device. The agents exit through the wide opening ofthe elongate tube, which is advantageously near the thrombus that is thetarget of the thrombolytic agents.

In another example implementation, the thrombus detection device may bedeployed using a simple sheath that may be inserted into the patient'sblood vessel. The distal end of the sheath may be placed near a desiredlocation. The desired location may be proximal to an existing filterthat may or may not be attached to a catheter body. The sheath may alsobe a sheath that already contains a catheter that may or may not includean attached filter device so that the sheath contains both the catheterdevice and the thrombus detection device.

In alternative embodiments, the thrombus detection device need notincorporate a flexible end member with a wide opening for guiding athrombus towards the opening to the lumen of the elongate tube.Referring to FIGS. 3A-4B, a thrombus detection device 300 includes acatheter having a tip portion 302, a thrombus detection portion 306 andan elongate tube portion 309 integrated as a single catheter member.

The thrombus detection portion 306 is disposed between the tip portion302 and the elongate tube portion 309 within a region encompassed by anattached IVC filter 304. The thrombus detection portion 306 includes aplurality of openings 312 extending longitudinally along the thrombusdetection portion 306. The plurality of openings 312 pass through a wallsurface of the thrombus detection portion 306 of the catheter and are influid communication with at least one tube lumen formed in the elongatetube portion 309 and the thrombus detection portion 306 of the catheter.The openings 312 may be equally or unequally spaced along the thrombusdetection portion 306 and may be positioned at any position about thecircumference of the thrombus detection portion 306 of the catheter. Theplurality of openings 312 may also comprise a first plurality ofopenings 312 on one side of the thrombus detection portion 306 andanother plurality of openings on the other side of the thrombusdetection portion 306.

The attached IVC filter 304 may be any suitable filtering deviceconfigured to capture embolic material of a size that is sufficient tocreate a risk of a pulmonary embolism if it is not filtered. In anexample implementation, the IVC filter 304 may be a self-expandingstructure made of a plurality of struts formed to capture a thrombus. Afirst plurality of struts may attach to the catheter body at the distalend of the elongate tube portion 309, and a second plurality of strutsinterconnect to provide a filtering structure. The IVC filter 304 may bea collapsible self-expanding filter structure that collapses when thethrombus detection portion 306 of the catheter is inserted into a sheath310, and self-expands when the thrombus detection portion 306 of thecatheter extends beyond the distal end of the sheath 310.

The thrombus detection portion 306 of the catheter body is disposed in aregion of the catheter body bounded by the IVC filter 304. The openings312 are in fluid communication with the tube lumen extending through theelongate tube portion 309 of the catheter. The proximal end of thecatheter may include a coupling as described above with reference to theembodiments of FIGS. 1-2D. A syringe coupled to the coupling may be usedto withdraw blood through the openings 312 and the tube lumen of theelongate tube portion 309 of the catheter.

The IVC filter 304 may be deployed and left in a patient's blood vesselfor a prescribed amount of time. While the IVC filter 304 is operatingin the patient's blood vessel, the IVC filter 304 may be checked todetermine if it is burdened by a thrombus. Typically, the IVC filter 304is checked prior to its removal. In order to check for a thrombus in theIVC filter 304, a syringe is coupled to the coupling at the proximal endof the catheter. The syringe is then used in an attempt to draw bloodinto the openings 312 and the elongate tube portion 309 of the catheter.If the IVC filter 304 does not contain any thrombi, the blood will beeasily drawn into the openings 312. If the IVC filter 304 contains athrombus of sufficient size to obstruct the openings, the blood will beobstructed from entry into the openings 312 when an attempt is made toaspirate the blood into the openings 312. As the size of the thrombusincreases, the number of obstructed openings 312 increases creating agreater obstruction of blood into the openings 312 and an increase indifficulty withdrawing blood. The relative increase in the difficulty ofwithdrawing blood provides an indication of the size of the mass ofthrombotic material burdening the IVC filter 304.

FIGS. 4A and 4B show another embodiment of a thrombus detection device400. FIG. 4A is a perspective view of the thrombus detection device 400.FIG. 4B is a detail view of the thrombus detection device 400 at DetailC in FIG. 4A. The thrombus detection device 400 in FIGS. 4A and 4Bincludes an elongate tube 402, a hub 404, a first syringe line 406having a first coupling 410, and a second syringe line 408 having asecond coupling 412. The elongate tube 402 includes a distal tubeportion 403 comprising a plurality of openings 416. The example elongatetube 402 shown in FIG. 4B includes a first thrombus detection opening416 a close to the tip and a substantially aligned second thrombusdetection opening 416 b a distance away from the first thrombusdetection opening 416 a. Additional openings 416 may be provided furtherproximally along the elongate tube 402. Additional openings 416 may alsobe provided diametrically opposite the first and second openings 416 aand 416 b.

The elongate tube 402 may include a first lumen in fluid communicationwith a first plurality of openings and a second lumen in fluidcommunication with a second plurality of openings. The first pluralityof thrombus openings may be distributed on one side of the distal tubeportion 403 and the second plurality of openings on the other side ofthe distal tube portion 403. The hub 404 provides fluid pathways so thatthe first lumen is in fluid communication with the first syringe line406 and the second lumen is in fluid communication with the secondsyringe line 408. As described above with reference to FIGS. 3A and 3B,the openings 416 may be spaced so as to quantify the size of the clotthat may be obstructing the blood withdrawal. By attempting to withdrawblood via lumens in fluid communication with openings on opposite sidesof the distal tube portion 403, one can determine whether one side ofthe IVC filter is more burdened than the other side. The indication ofthe size of the clots and of the distribution of the thrombotic materialin the IVC filter provides information that may be used to determine howbest to manage the clots.

Example embodiments of devices for detecting a thrombus are describedabove with reference to FIGS. 1-4B. The examples described withreference to FIGS. 1-2D use an elongate tube having a single lumen thatopens to a distal tube portion with a lumen having an inner diameterthat increases to a wide opening. Thrombus detection is achieved whenattempting to draw blood. The presence of a thrombus in the distal tubeportion lumen obstructs blood from flowing into the elongate tube. Theexamples described with reference to FIGS. 3A-4B use an elongate tubehaving either a single lumen or multiple lumens in fluid communicationwith openings at the distal end of the elongate tube.

A method to detect a thrombus within a blood vessel may be performedusing any suitable example of the above described devices for detectinga thrombus. The method comprises the steps of:

-   a. introducing an elongate tube having at least one opening in a    distal end of the elongate tube into the blood vessel.-   b. positioning the distal end of the elongate tube at a site of    interest;-   c. attaching a syringe to a coupling at a proximal end of the    elongate tube; and-   d. using the syringe to withdraw blood through the elongate tube    where a thrombus in the at least one opening of the flexible member    obstructs the blood withdrawal indicating the presence of the    thrombus.

The site of interest indicated in step a may be the region encompassedby a filter. The distal end of the elongate tube may be brought to theregion encompassed by the IVC filter through a lumen of a catheter or asheath extending in the patient's blood vessels to the regionencompassed by the IVC filter. The filter may or may not be attached toa distal end of a catheter. The method may thus include the steps of:

-   a. inserting a sheath into the blood vessel; and-   b. inserting the elongate tube to the blood vessel through the    sheath.

Alternatively, the method may include the steps of:

-   a. inserting a catheter body having a lumen with a distal port on a    distal end of the catheter body and a proximal port on a proximal    end of the catheter body into the blood vessel; and-   b. inserting the elongate tube into the proximal port of the    catheter body until the distal end of the elongate tube exits the    distal port.

In one embodiment, a device for detecting the presence of a thrombus ina patient's blood vessel is disclosed and comprises: an elongate tubecomprising a tube lumen extending at a substantially constant innerdiameter from a proximal end opening at a proximal end to a distal tubeportion comprising a plurality of openings in fluid communication withthe tube lumen; and a coupling attached at the proximal end opening ofthe elongate tube, the coupling configured to configured to removablycouple a syringe to the first opening of the elongate tube where thesyringe is used to draw blood through the plurality of openings andthrough the tube lumen of the elongate tube; wherein detection of athrombus is determined by drawing blood through the openings and throughthe elongate tube, and indicating the presence of a thrombus when lessblood can be drawn than expected due to obstruction of at least some ofthe plurality of openings. The coupling is a luer-lock. The elongatetube is made of a polymeric material, a metallic material, or acombination thereof. The plurality of openings extend longitudinallyalong the distal portion of the elongate tube. The plurality of openingsincludes a first plurality of openings extending along one side of theelongate tube and a second plurality of openings extending along anopposite side of the elongate tube. The tube lumen of the elongate tubeis a first lumen, the tube lumen comprises a second lumen, the proximalend opening is a first proximal end opening in fluid communication withthe first lumen, the elongate tube comprises a second proximal endopening in fluid communication with the second lumen; the firstplurality of openings is in fluid communication with the first lumen;and the second plurality of openings is in fluid communication with thesecond lumen. Each of the plurality of openings are spaced at equaldistances longitudinally along the distal tube portion of the elongatetube, and where the equal distances provide an indication of clot sizewhen multiple openings may be obstructed as the size of the thrombusincreases.

Thus there have been described examples of a thrombus detection devicewhich include, generally, an elongate tube extending from a firstopening at a proximal end to an at least one opening at a distal end. Acoupling is formed at the first opening to permit attachment of asyringe that may be used to withdraw blood through the elongate tube.These and other aspects of the present invention are provided by way ofnon-limiting examples, with the claims appended hereto serving to definethe scope of the subject matter regarded as the invention.

What is claimed is:
 1. A device for detecting the presence of a thrombus in a blood vessel comprising: a. an elongate tube comprising a tube lumen extending at a substantially constant inner diameter from a first opening at a proximal end to a distal tube portion comprising a distal portion lumen extending at an increasing inner diameter to a second opening wider than the first opening, the second opening being sufficiently wide to permit entry of a thrombus into the distal portion lumen; and b. a coupling at the proximal end of the elongate tube configured to removably couple a syringe to the first opening of the elongate tube where the syringe is capable of drawing blood into the distal portion lumen and through the tube lumen of the elongate tube, an amount of blood drawn into the distal portion lumen and through the tube lumen of the elongate tube being capable of indicating the presence of thrombus.
 2. The device of claim 1, where the elongate tube comprises: a. a tube member forming the tube lumen in a proximal tube portion of the elongate tube, the tube member extending from the proximal end of the elongate tube to a distal tube member opening of substantially the same size as the first opening of the elongate tube; b. a flexible end member forming the distal tube portion of the elongate tube, the flexible end member having a first end member opening configured to attach to the distal tube member opening, the flexible end member extending distally to form the distal portion lumen.
 3. The device of claim 1, where the elongate tube is formed as a single tubular member, and the coupling is a luer-lock.
 4. The device of claim 2, where the flexible end member is made of a polymeric material, a metallic material, or a combination thereof.
 5. The device of claim 4, where the single tubular member forming the elongate tube is made of a polymeric material, a metallic material, or a combination thereof.
 6. The device of claim 2, where the flexible end member is in a generally conical shape between the first flexible member opening to the second opening wider than the first opening.
 7. The device of claim 4, where a distal end of the single tubular member is formed in a generally conical shape.
 8. A flexible end member for detecting a thrombus in a blood vessel comprising: a substantially tubular member extending from a first end member opening at a proximal end to a second end member opening wider than the first end member opening at a distal end, where the first end member opening is configured to connect to a tube member to permit blood withdrawal through the substantially tubular member when a thrombus is not present at the second flexible member opening.
 9. The flexible member of claim 8, where the substantially tubular member is made of a polymeric material, a metallic material, or a combination thereof.
 10. The flexible member of claim 9, where the substantially tubular member is in a generally conical shape between the first end member opening to the second end member opening wider than the first end member opening.
 11. A medical device comprising: a. a catheter body having a distal port positioned in a distal portion of the catheter body, the distal port being in fluid association with a catheter lumen extending to a proximal port in a proximal portion of the catheter body; b. an IVC filter coupled to the distal portion of the catheter body and positioned such that the distal port opens at a proximal side of the IVC filter; c. an elongate tube comprising a tube lumen extending at a substantially constant inner diameter from a first opening at a proximal end to a distal tube portion comprising a distal portion lumen extending at an increasing inner diameter to a second opening wider than the first opening, the second opening being sufficiently wide to permit entry of a thrombus into the distal portion lumen, where the distal tube portion is configured to collapse for insertion into the catheter lumen at the proximal port and to expand when the distal tube portion extends out of the catheter lumen at the distal port; and d. a coupling in fluid communication with the first opening of the proximal end of the elongate tube, the coupling configured to removably couple a syringe to the first opening of the elongate tube where the syringe is capable of drawing blood into the distal portion lumen and through the tube lumen of the elongate tube.
 12. The medical device of claim 11, where the elongate tube comprises: a. a tube member forming the tube lumen in a proximal tube portion of the elongate tube, the tube member extending from the proximal end of the elongate tube to a distal tube member opening of substantially the same size as the first opening of the elongate tube; b. a flexible end member forming the distal tube portion of the elongate tube, the flexible end member having a first end member opening configured to attach to the distal tube member opening, the flexible end member extending distally to form the distal portion lumen.
 13. The medical device of claim 12, where the elongate tube is formed as a single tubular member and where the coupling is a luer-lock.
 14. The medical device of claim 13, where the flexible end member is made of a polymeric material, a metallic material, or a combination thereof, and where the single tubular member forming the elongate tube is made of a polymeric material, a metallic material, or a combination thereof.
 15. The medical device of claim 13, where the flexible end member is in a generally conical shape between the first flexible member opening to the second opening wider than the first opening.
 16. The medical device of claim 14, where a distal end of the single tubular member is formed in a generally conical shape.
 17. A method to detect a thrombus within a blood vessel, comprising the steps of: a. introducing an elongate tube into the blood vessel, the elongate tube having at least one opening in a distal end of the elongate tube; b. positioning the distal end of the elongate tube at a site of interest; c. attaching a syringe to a coupling at a proximal end of the elongate tube; and d. withdrawing blood through the elongate tube where a thrombus in the at least one opening of the flexible member obstructs the blood withdrawal indicating the presence of the thrombus.
 18. The method of claim 17, where the step of introducing the elongate tube into the blood vessel comprises: a. inserting a sheath into the blood vessel; and b. inserting the elongate tube to the blood vessel through the sheath.
 19. The method of claim 17, where the step of introducing the elongate tube into the blood vessel comprises: a. inserting a catheter body having a lumen with a distal port on a distal end of the catheter body and a proximal port on a proximal end of the catheter body into the blood vessel; and b. inserting the elongate tube into the proximal port of the catheter body until the distal end of the elongate tube exits the distal port.
 20. The method of claim 17, where the catheter body includes an IVC filter coupled to the distal end of the catheter body such that the distal port of the catheter body is positioned proximal to the IVC filter, the method further comprising after the step of inserting the catheter body into the blood vessel, deploying the IVC filter. 